program ckn;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  k,n,kf,nf,knf,i: integer;
begin
  kf:=1;
  nf:=1;
  knf:=1;
  readln(k);
  readln(n);
  for i:=1 to k do
    kf:=kf*i;
  for i:=1 to n do
    nf:=nf*i;
  for i:=1 to (n-k) do
    knf:=knf*i;
  writeln(nf div (kf*knf));
  readln;
end.
 